Laguna de Bay 2013 Ecosystem Health Report Card Ibalik ang diwa ng lawa Restore the ecological balance of the lake Laguna de Bay, a special ecosystem Laguna de Bay is the largest inland waterbody in the Philippines and the third largest in South East Asia. The Lake has a surface area of 900 km², with an average depth of 2.5 meters and an elevation of about 1 meter above sea level. It is bordered by the province of Laguna in the east, west, and southwest, the province of Rizal in the north to northeast, and Metro Manila in the northwest. The Lake features three distinct bays; the West Bay, Central Bay, and East Bay that converge at the South Bay. The West Bay watershed is the most populated and heavily developed, mainly because it includes part of Metro Manila, while the East Bay is the least. The West and Central Bays are separated by Talim Island, the biggest and most populated island within the Lake. The Lake’s only outlet is the Napindan Channel which is connected to Manila Bay via the Pasig River. Natural resource values and human activity threats Metro Manila Manila Marikina Bay Rizal Pasig River Province River Tanay Napindan River Channel Sta. Maria River West Bay Central Bay Talim Island Tunasan- East Bay Cuyab River Laguna de Bay South Bay Pagsanjan San Cristobal River River Santa San Juan Mt. Laguna Cruz River River Makiling Province VALUES: Laguna de Bay is a multi-use water resource, supporting agriculture, livestock and poultry , and various industries . Local populations rely on both aquaculture in fish pens and cages and traditional fishing for commerce and food. Water extraction provides drinking water, industrial cooling and hydroelectric power generation . The Lake provides transportation and recreational opportunities for the general public. Laguna de Bay and its watershed are rich in biodiversity, serving as a flyway sanctuary for migratory birds . THREATS: The impacts of rapid population growth and urbanization are causing severe stress to the Lake environment and the watershed. Untreated domestic sewage (i.e., informal waterway settlements ), sediment and nutrients from agricultural, industrial, and mining activities flow into either the Lake or its many tributaries, leading to poor water quality and ultimately, harmful algal blooms , and fish kills. Invasive species such as the clown knife fish threaten native fish stocks. To attempt to regulate saltwater intrusion , flooding, and pollution flowing between the Pasig River and the Lake, the Napindan Hydraulic Control Structure was constructed in 1983. However, it was not operated to regulate saltwater intrusion due to strong protest from the fisheries sector since periodic salt water intrusion is favorable to fisheries. How ecosystem health is measured Recognizing the importance of Laguna de Bay, this first ecosystem health report card is designed to provide a Water quality indicators better understanding of the current ecosystem health, Nitrates in excess amounts cause dramatic particularly as water quality improvement strategies are increases in aquatic plant growth and changes in developed. the types organisms that live in the Lake. Sources include fertilizers, drainage from livestock feeds, as well as domestic and industrial discharges. Phosphates come from agricultural runoff, animal waste and sewage. Phosphorous is also one of the main components of synthetic detergents. Chlorophyll a measures the amount of phytoplankton that can cause algal blooms. Algal blooms by blue-green algae are an indicator of deteriorating water quality and pollution. View of the West Bay watershed. Photo: Vanessa Vargas Dissolved oxygen (DO) is vital for the survival of Two workshops were conducted. The first workshop fish and benthic organisms in the Lake. in December 2013, discussed the framework for the report card; identified the target audience and proposed indicators, sub-indicators and thresholds; and determined Biological oxygen demand (BOD) is the amount the key messages. of oxygen required by microorganisms for stabilizing biologically decomposable organic matter in water During the second workshop in June 2015, the initial BOD under aerobic conditions. High BOD levels are grades for the four sections of the bay were calculated associated with organic pollution, such as sewage. and the report card framework was drafted. Indicators for Water Quality and Fisheries were selected to measure the ecosystem health of Laguna de Bay. Taken together, Total coliforms is a measure of animal bacteria these indicators stand for the values of the Lake and the that enter the Lake by direct deposition of waste threats that it is currently facing. in the water and runoff from areas with high concentrations of animals or humans. Fisheries Indicators Zooplankton ratio can be used to indicate changes in the trophic state of the Lake, level of eutrophication and warming history. A decreasing calanoid to cyclopoid ratio indicates deteriorating trophic state; the lower the calanoids, the higher the trophic state of the Lake. In Laguna de Bay, the only remaining calanoid copepod is the invasive Arctodiaptomus dorsalis, which has already displaced previously recorded native calanoid Participants of the Second Laguna de Bay Report Card Workshop. species in the Lake. List of participants: Nancy Bermas and Daisy Padayao (Partnerships in Environmental Management for the Seas of East Asia); the Laguna Lake Development Authority Technical Working Group: Adelina Santos-Borja, Native fish species composition measures the Jocelyn Sta. Ana, Rose Bonifacio, Neil Varcas, Ireneo Bongco, Rosemary proportion of native against introduced/invasive Cabrera, Gregory Ongjoco, and Marilyn Apacionado; Dr. Adelaida Palma species in major catch composition. (Bureau of Fisheries and Aquatic Resources); Dr. Gil Jacinto (University of the Philippines-Marine Science Institute); Dr. Macrina Zafaralla (University of the Philippines-Los Baños); Dr. Rey Papa and Milette Mendoza Catch per unit effort (CPUE) is computed from (University of Santo Tomas); and the Science communication team: the average total daily catch and the total number Dave Nemazie, Dr. Simon Costanzo, and Vanessa Vargas (University of of fishing hours. Maryland Center for Environmental Science). 2013 Laguna de Bay ecosystem health report card LAGUNA DE BAY Laguna de Bay scored a low passing mark, 76%, a C-, in water quality. The Lake consistently is within the Department Laguna de Bay Land Cover of Environment and Natural Resources lake and reservoir Development C- (DENR) guidelines for class C waters in river Crops Water Quality DO, BOD, nitrate, and total coliforms. fish pen and/or cage Forest However, it scored 0% in chlorophyll a BOD Laguna Lake Mangrove Forest and 59% in phosphates. Water quality Development Grassland was affected by high population and Authority (LLDA) Marshland/Swamp industralization. sampling stations Shrubs Rizal The Lake received an F in Fisheries (48%), Fishpond with 53%, 68%, and 22% scores Open/Barren F in fish native species composition, Fisheries Metropolitan zooplankton ratio, and catch per unit effort (CPUE), respectively. Invasive fish Manila species and competition among fisherfolk contributed to the low scores. Even though the DENR guidelines are met in most water quality indicators, the chlorophyll a, phosphates, and zooplankton ratio scores show that the Lake is highly eutrophic. These results have a negative impact on the fisheries of Laguna de Bay. Overall, these scores are not only a cause of concern for fisheries, but the whole community and all the industries supported by the Lake. WEST BAY CENTRAL BAY How are the scores calculated EAST and what do they mean? BAY The 2013 Laguna de Bay report card measured indicators for water quality and fisheries for the West, Central, East, and South bays. Six water quality Cavite indicators were compared to the Department of Environment and Natural Resources (DENR) guidelines for class C waters (suitable for fisheries and recreation) which were then combined and represented as a percent score for each bay. The three fisheries indicators were calculated as ratios or percentages that are then combined as a percent score for each bay. The SOUTH BAY grading scale follows the typical scale used in Philippine universities. Luzon 91–100%: All the indicators meet desired levels. Quality of water PHILIPPINES in these locations tends to be very good, most often leading to Metro Manila A preferred habitat conditions for aquatic life. 83–91%: Most indicators meet desired levels. Quality of water in these locations tends to be good, often leading to acceptable Laguna B habitat conditions for aquatic life. 75–83%: There is a mix of good and poor levels of indicators. Quality of water in these locations tends to be fair, leading to C sufficient habitat conditions for aquatic life. Visayas 70–74%: Some or few indicators meet desired levels. Quality of water in these locations tends to be poor, often leading to D degraded habitat conditions for aquatic life. 0 8 16 Kilometers 0–70%: Very few or no indicators meet desired levels. Quality of water in these locations tends to be very poor, most often Mindanao F leading to unacceptable habitat conditions for aquatic life. 2013 Laguna de Bay ecosystem health report card WEST BAY The West Bay has the second lowest water quality score, 76%. It is the most heavily developed side of Laguna de Bay and Laguna de Bay Land Cover most populated. For 2013, its DO, BOD and nitrate were lake and reservoir Development C- within DENR's guideline for class C waters (100%) and its total Water Quality coliforms at 98%. However it has the second lowest score river Crops in phosphates (56%) and like all the bays, received a 0% in Forest BOD fish pen and/or cage chlorophyll a. This scores reflect its high population density and Laguna Lake Mangrove Forest the need to reduce phosphorus runoff into the Lake. Development Grassland The West Bay has the second highest fisheries score of 55% Authority (LLDA) Marshland/Swamp F (F), with a 62% score in zooplankton ratio, CPUE (35%), and Fisheries sampling stations Shrubs the second highest score in native fish species composition Rizal at 68%.